Henry james johnson



(No Model.)

'H. J. JOHNSON.

SLIDE VALVE SEAT.

No. 300,372. Patented June 17, 1884.

WiTN E SSE 5 llrvi'rnn Sra'rns Parent @rrrcri.

IIENR-Y JAMES JOHNSON, OF PROVIDENCE, RHODE ISLAND, ASSIGNOR TO HEN tY\V. GARDNER, OF SAME PLACE.

SLI DE=VALVE SEAT.

SPECIFICATION forming part of Letters Patent No. 300,372, dated June 17,1884-.

Application filed February 29, 1884. (No model.)

T0 aZZ 2071,0122, may concern.-

Be it known that I, IIENRY Janus J OHN- SON, ofthc city and. countyofProvidence, and State of Rhode Island, have made an invention of certainnew and useful Improvements in Slide-Valve Seats for Steam-Engines andother Purposes; and I do hereby declare that the following, inconnection with the accompanying drawings, is a full, clear, and exactdescription and specification of the same.

val veseats of such sli (lo-valves have been made According to hithertoin one of two modes. one mode the valve-seat is asegment of a eyl inderlarger than a half-cylinder, andis forced into the bore of the shell. Inanother mode the valve-scat a smaller segment than half a cylinder, andis held in place by long wedges or keys driven longitudinally above itsedgesin seats provided for the purpose. The first mode is, in myopinion, objectionable, because of the difliculty of getting the seatout of the shell, while the second mode also is, in my opinion,objectionable, because of the expense of the key-seats and keys and thespace occupied by the latter. According to my system of construction thevalveseat is a segment whose bearing-surface on the shell of thevalve isless than half the bore of the shell, so that it can be readilyinsertedtherein and removed, and it is secured to the shell by screw-bolts thatpass transversely through the shell or chest, so that the cost ofsecuring thevalvc- 'seat is small, and the seat can be readilyloosencdfor removal by simply unscrewing the bolts.

In order that theinvention may be fully understood, I have representedin the accompanying drawings and will proceed to describe my improvedvalve construction as applied to the exhaust-valves of the cylinder of asteamengine.

Figure 1 of said drawings represents a cen tral longitudinal section ofthe steam-cylinder and valves. Fig. 2 represents a partial exhaust-valvewith a part of the butt of the cylinder in elevation.

In the said example the steam-cylinder A has the shells or chests B B ofthe exhaustvalves cast in one piece with it, and these shells are boredout cylindrically. The valve 0 is a five-ported slide-valve fitted toslide endwise in the shell. The valve-seat D is a segment of a cylinderof acurvature tofit snug to the bore of the shell, and slotted to formthe ports or passages for the steam, and the seat is smaller than half acylinderthat is, its bearing-surface on the shell is less than half acylinder. This seat is inserted endwise in the shell or chest 13, thebonnet f of the shell being removable for that purpose, as is usual. Thevalveseat is secured by two screwbolts, 0 eone at each end of theseateach bolt being entered transversely of the shell through a holebored for that purpose. As the bearing ofthe valve-seat on the shell isless than a se1ni-cylinder, it can be readily insorted into the bore ofthe shell and withdrawn therefrom, and when it is in place the boltshold it firmly to the shell, and the removal of So the bolts frees it sothat it can be readily removed. The necessity of forcing the valveseatinto its place is obviated, and as the boltholes in the shell are madeby a simple drilling operation, the cost of securing the valve- 8 5 seatis small.

The shell of the valve may of courscbe made separately from thesteam-cylinder or other device with which it is to operate, and may besecured thereto by bolts.

I claim as my invention- 1. The segmental cylindrical valve-seat,constructed, substantially as before set forth, with its bearing smallerthan a semi-cylinder and perforated transversely for screw-bolts.

2. The combination, substantially as before set forth, of the shell ofthe valve, the segmental cylindrical valve-seat constructed with abearing less than a semi-cylinder, and the transverse screw-bolts bywhich the first two 100 are secured to each other.

In witness whereof I have hereto set my hand this 23d day of February,A. D. 1884.

HENRY JAMES JOHNSON.

Vitnesses:

GARDNER O. ANTHONY, WALTER F. Brown transverse section of the saidcylinder and one 5 5

